The goal of this article is to contribute to our understanding of glides – their properties and distribution in underlying and surface representations, the range and the features of their various phonetic manifestations, and their role in the assignment of syllable structure and stress. Spanish provides a rich opportunity for carrying out this study because of the special properties of high vocoids in this language, which are systematically realised as glides in particular contexts: they can function as both onsets and rhymes; they can occur in prepeak, peak and postpeak position; up to four can occur in a row; and they take on a wide range of surface realisations.

In the pursuit of our goal, we confront a problem in Spanish phonology that has tantalised investigators for the better part of this century, and rightly continues to do so. The conundrum involves the two sets of phonetic segments we transcribe as [i j y [barred dotless j] ž jˇ] and [u w γw gw] (articulatory descriptions and feature characterisations are given below). Classical structuralist studies, and some current analyses as well, see the problem as the taxonomic exercise of assigning each of these segments to a particular ‘phoneme’ or ‘underlying segment’. Our study includes the notion of phonemic inventory, but considers it as only one of many intersecting issues involved in the attempt to elucidate aspects of the mental representations that native Spanish speakers employ in their phonological computations. We undertake to raise the level of discourse concerning the problem at hand not only by redefining it but also by enlarging the set of data and descriptive issues brought to bear on it and by situating the discussion in a rich theoretical context.